Spacewalkers get ready to finish station's power supply

Big job in orbit: 15 tons of equipmentSpacewalkers aim to compete work on station's power supply

MARK CARREAU, Copyright 2009 Houston Chronicle

Published
5:30 am CDT, Wednesday, March 18, 2009

Japan Aerospace Exploration Agency astronaut Koichi Wakata, STS-119 mission specialist, works on one of the decks.

Japan Aerospace Exploration Agency astronaut Koichi Wakata, STS-119 mission specialist, works on one of the decks.

Photo: AP

Photo: AP

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Japan Aerospace Exploration Agency astronaut Koichi Wakata, STS-119 mission specialist, works on one of the decks.

Japan Aerospace Exploration Agency astronaut Koichi Wakata, STS-119 mission specialist, works on one of the decks.

Photo: AP

Spacewalkers get ready to finish station's power supply

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Astronauts at the controls of two robot arms gingerly handed the last major American piece of the international space station back and forth on Wednesday, slowly maneuvering the 45-foot solar power component into position for installation.

Shortly after noon Thursday, shuttle Discovery astronauts Steve Swanson and Ricky Arnold, a former high school science teacher, will float outside the space station for a six-to-seven hour spacewalk. After making their way to the base’s far right end, they will bolt the 31,000 pound power-generating module to the facility.

The final steps in the installation are planned for Friday afternoon, when astronauts will unfurl the module’s two 115-foot solar panels.

The shuttle Discovery, staffed by seven astronauts, delivered the $298 million electricity-generating module to the orbital outpost on Tuesday.

Minor damage shown

Photos of the shuttle taken by space station astronauts before the craft docked revealed three areas of concern, officials said. A tile on the left wing flap near the shuttle’s fuselage was slightly damaged. There was a small fray in the insulation surrounding the door over the nose-wheel landing gear enclosure, and there were two small irregularities in the insulation on the left side of the tail section. After several hours of deliberation, the mission’s managers decided the damage would not affect the crew’s safe return and that additional inspections were unnecessary.

The day’s activity to unload the new solar power module unfolded at a snail’s pace.

Multiple handoffs between the robot arms were necessary to carry the unwieldy power module around the station’s older American, European and Japanese science modules.

Controlling placement

Four astronauts were posted at control stations inside Discovery and the orbital base. They first hoisted the power module out of the shuttle’s cargo hold with the space station’s 57-foot-long robot arm. The arm was mounted atop a rail car on the station’s central power system truss, allowing it to move like a construction crane on Earth.

Two hours later, the station crane handed the power component to the shuttle’s 51-foot-long robot arm.

The shuttle’s arm held on to the component for about four hours while the station’s robot arm rolled about 100 feet to the station’s far right side. There, the second handoff occurred when the station’s arm took possession of the component for the night.

The newest module will plug into a space station electrical grid that has been operating with three similar power modules. The latest addition will double the electricity available for science experiments.